This prospective observational study aims to advance our knowledge of the natural history and abnormal alteration in vaginal microbial flora, and to identify risk factors that are associated with these changes. A total of 3600 healthy, non-pregnant women of reproductive age have been enrolled and were followed in Birmingham, Alabama for one year (baseline visit plus once every three months afterwards, totaling five visits). Detailed information on sociodemographic status, medical history, hygiene practice, sexual behavior and psychosocial stress was collected through in-person interviews. Routine gynecological and dental examinations were carried out during the study visits. Samples of vaginal secretion and blood were collected. Laboratory tests to quantify vaginal microbial flora and to identify infection of bacterial vaginosis as well as common sexually transmitted diseases were conducted. Sub-studies evaluate the day-to-day change in vaginal flora, and the effect of cessation of douching. The final study visits were completed in June 2003, and various analyses are underway. One analysis, currently in press, describes the association between personal hygienic behaviors other than douching and bacterial vaginosis. It is reasoned that if douching were merely a response to symptoms of BV (rather than a cause of BV) then other feminine hygiene behaviors (such as use of deodorant sprays, powders, wipes, etc) would also be more common among women with BV. However, when these behaviors were found by-and-large not to be statistically significantly associated with BV. This suggests that douching is not merely a response to BV symptoms. As noted above, whether BV is sexually transmitted is uncertain. It is also not understood why BV is twice as prevalent among African-American compared to white women. To explore both of these possibilities, the association between race of the sex partner and incidence of BV was evaluated. Among white women, having an African-American male sex partner was associated with a doubled incidence of BV compared to having only white male sex partners. The lowest incidence was observed in times without sexual activity. There were too few African-American women who had only white male sex partners to study the race of male sex partners. A third analysis, recently begun, evaluates the association between bacterial vaginosis and periodontal disease. Finally, plans for 2010 and beyond include application of metagenomic techniques (amplification and sequencing of bacterial 16S ribosomal genes) to study the basic microbiology of BV.